Generally, a color filter for liquid crystal display consists of a large number of color triplets, each made up of three color pixels (red, green, and blue), formed on a transparent substrate. To enhance the contrast of the display, these pixels are distributed with specific intervals over a light-shielding region, which is called the black matrix because of its color on the screen.
Most of the conventional color filters use a black matrix produced by the photolithography, and comprise a thin metal film with a fine pattern. The metals used for such black matrices include Cr, Ni, and Al, and the methods used for producing them include such vacuum film forming methods as sputtering and vacuum deposition. To form a fine pattern, the photolithography is used in most cases to form a pattern on photoresist, and this photoresist pattern is then used as etching mask to etch thin metal film. The thin metal film produced by this process has the same fine pattern as that on the photoresist.
The methods for producing pixels include the dyeing of a dyeable medium formed by the photolithography, the use of a photosensitive composition consisting of dispersed pigment, the etching of non-photosensitive composition consisting of dispersed pigment, and the electrodeposition of pigment onto a patterned electrode, as well as such low-cost methods as the formation of colored portions by ink jet or other printers.